Satellite Problems With Arctic Sea Ice Measurement

Skeptical sorts across the cryoblogosphere are in meltdown mode at the moment. They seem to be unaware that satellites don’t last forever in the harsh environment of space, and the individual scientific instruments carried by a satellite don’t either. Some failures are more spectacular than others however. By way of illustration here’s one recent report from Space.com:

The February [2015] explosion of an American military satellite may cause some problems for orbiting spacecraft after all, a new study reports.

The U.S. Air Force’s 20-year-old Defense Meteorological Satellite Program Flight 13 (DMSP-F13) craft blew apart on Feb. 3 after experiencing a power-system faillure. Analyses by the European Space Agency and other organizations found that the cloud of space junk generated by the explosion shouldn’t pose much of a threat to their missions, but the new research suggests that not all spacecraft are in the clear.

Another DMSP satellite started pushing up the metaphorical daisies earlier this year. Last month Space Flight Now reported that:

The U.S. Air Force has been unable to send commands to the service’s newest weather satellite for nearly a month, and engineers are trying to determine if the spacecraft can be salvaged, officials said last week.

The polar-orbiting Defense Meteorological Satellite Program Flight 19, or DMSP F19, spacecraft stopped responding to orders from the ground Feb. 11, the Air Force said in a March 3 press release.

“At this time, it is not known what caused the anomaly or if the satellite will be recovered, and the anomaly is under investigation,” the Air Force said. “There are no other known issues with the satellite.”

Designed for a five-year service life, DMSP F19 launched April 3, 2014, from California atop a United Launch Alliance Atlas 5 rocket. It is the newest in the Air Force’s series of DMSP weather observatories designed to help forecasters predict storms, clouds, fog and dust storms that could inhibit global military operations.

The data provided by the Special Sensor Microwave Imager/Sounder (SSMIS) instrument carried aboard several of the DMSP series of satellites is used by the National Snow and Ice Data Center to calculate their Sea Ice Index metric of Arctic sea ice extent. However suddenly Boulder has a problem. As we reported earlier this week the SSMIS sensor carried by DMSP F17 appears to be malfunctioning. This can be seen in this visualisation of the data from the European Ocean and Sea Ice Satellite Application Facility(OSI-SAF):

Look closely at the top centre of the image to see a large patch of spurious “sea ice”. Here’s the resulting SII extent graph from the NSIDC:

Makes you wonder how long this has been going on and if the anomalously low readings we’ve seen for awhile are due to a slow sensor degradation.

Time will tell.

For a more realistic interpretation of the facts we suggest that instead of reading the propaganda perpetrated at WUWT you instead examine this graph derived using data from the AMSR2 sensor on board the Japanese SHIZUKU satellite:

Mr. Watts evidently takes a very US centric view of these matters, since he neglected to report this timely news bulletin from the OSI-SAF:

Due to the previously reported problems with one of the channels on SSMIS onboard DMSP F17, OSI SAF is now working on replacing DMSP F17 with DMSP F18 in our sea ice products.

Currently, the switch to F18 has been implemented for the ice concentration product (OSI-401). The product dated 20160410 has been reprocessed and is available on our FTP server, ftp://osisaf.met.no/prod/ice/conc/ and ftp://osisaf.met.no/archive/ice/conc/2016/04

The ice edge and type products (OSI-402 and OSI-403) will be updated to use F18 tomorrow, 2016-04-12.

We have no way to know if this has been a gradual decrease followed by a failure, so yes, it’s certainly possible that the previous data is bad. Doesn’t mean it is, but we’d be fools not to check.

We suggested a simple check:

Why not compare the NSIDC’s SSMIS data from F-17 with JAXA’s AMSR2 data from Shizuku? Wouldn’t that do the trick?

Willis replied:

I meant that just from the bad reading alone, we don’t know if the previous data is bad. Yes, we can check it in the way you suggest and other ways … which is why I said we’d be fools not to check.

We think that if he does his due diligence he will find that he is in actual fact engaged on a fool’s errand, but time will indeed tell. Let’s wait and see what Willis n Willard can come up with, shall we? Meanwhile we also cannot help but wonder what the dynamic duo might make of our own due diligence replicating the results of another collaboration of theirs:

Of course Watt’s has animosity towards Mosher, because in his warped view of reality Steven has gone over to the “dark” side. What I found hilarious is that Willard kept attacking Neven about neglecting to have a dedicated thread for the issue even though it was well covered at both the forum and blog. Isn’t that a little odd for a man whose blog has heard no mention of the recent “blowtorch” in the Arctic, deadly heat wave in India, hail larger than baseballs in Texas, as well as the droughts in Africa and Asia….nothing to see here. Wasn’t it Saul who tried in vain to bring the Greenland warning to the attention on the clueless Joe post at the end of March?

On a positive note we have learned that the mention of the ASIB and Neven get comments vanished…WUWT?

Wow, Jim, you’re seeing my comment. So, how do I get to that second comment page (tried changing the URL, didn’t work)? Not that I’m that interested in reading everything on WUWT, but someone was telling porky pies about what I had said earlier this week on the ASIB.

That arrived in my inbox Neven. I can’t see your comment at WUWT, or indeed the gremlin infested page 2. I can’t see my own most recent comment for that matter. Par for the course on the porky pie production line!

Once upon a time Judy used to write papers about the Arctic. That sounds like a fairy tale now though, does it not?

NSIDC has suspended daily sea ice extent updates until further notice, due to issues with the satellite data used to produce these images. The vertically polarized 37 GHz channel (37V) of the Special Sensor Microwave Imager and Sounder (SSMIS) on the Defense Meteorological Satellite Program (DMSP) F-17 satellite that provides passive microwave brightness temperatures is providing spurious data. The 37V channel is one of the inputs to the sea ice retrieval algorithms, so this is resulting in erroneous estimates of sea ice concentration and extent. The problem was initially seen in data for April 5 and all data since then are unreliable, so we have chosen to remove all of April from NSIDC’s archive.

It is unknown at this time if or when the problem with F-17 can be fixed. In the event that the sensor has permanently failed, NSIDC is working to transition to either the DMSP F-18 or possibly the JAXA Advanced Microwave Scanning Radiometer 2 (AMSR2) on the Global Change Observation Mission – Water (GCOM-W) satellite. Transitioning to a different satellite will require a careful calibration against the F-17 data to ensure consistency over the long-term time series. While this transition is of high priority, NSIDC has no firm timeline on when it will be able to resume providing the sea ice time series.

It looks like JAXA’s AMSR2 is the go to source for the foreseeable future. Fortunately “Wipneus” has that angle well covered:

It just got more painful with Watts putting up a guest blog by some guy claiming that global sea ice is making a remarkable comeback. The recovery has begun, just a day or two after Watts announces the important discovery of a failing satellite sensor. 😐

Having taken Neven’s hint and glanced at WUWT again I discover that Willard is now promoting the self same nonsense as Judy Curry (see the “Tweet” above). We started to deconstruct Willis Eschenbach’s HadISST antics only a couple of days ago:

Bob Grumbine has been (successfully!) commenting at WUWT, but seems to be suffering under a misapprehension about some of the satellites discussed above. Here’s my so far vain attempt to straighten things out:

A packet of peanuts to the first person who spots my comment in the wild over at Watts Up With That!

Notice (04/19/2016): Daily sea ice concentration updates have improved. On 04/05/2016 a change in the solar panel position to shade the nitrogen tank on board the Defense Meteorological Satellite Program (DMSP) F-17 satellite was made. In doing so, the integrity of the vertically polarized 37 GHz channel (37V) of the Special Sensor Microwave Imager and Sounder (SSMIS) was compromised. This is a primary channel used in the sea ice processing. On 04/13/16 an additional change in the solar panel position was made.This change has improved the problems we were seeing in the 37V GHz channel. The affected daily files from 04/05 – 04/13 have been removed from distribution.

Now that you come to mention it I’m quite sure I was looking at the wrong thread!

In my defence one could conceivably argue that Saul should logically have commented on the most recent thread on the topic. Be that as it may, Mr. Watts has evidently no conceivable excuse for not singing the praises of solar panel realignment to the rafters of his hallowed halls.

You may get a smile if you reread the beginning of the thread I linked…To me it is obvious why he stayed on that thread. Willard and clueless Joe Bastardi certainly came out the losers in that exchange.
What I find curious is the conspicuous absence of dbs when Saul is posting.

Non Prof. Watts evidently doesn’t check the NSIDC web site very often, or indeed the comments on his very own blog for that matter. Apart from Phil & Saul’s comments regarding F-17’s miraculous recovery I sent him this virtual postcard this morning (UTC):

Expect it will be a minimum of two months before NSIDC-0081 is updating regularly again with a new vetted source and the Sea Ice Index is processing that new input.

The reason for the delay is that:

The Index relies on data that come from the DMSP F17 satellite. However, these data have not been reliable since early April; so the [email protected] team has not been able to update the Sea Ice Index since 31 March 2016.

Sea Ice Index processing uses an NSIDC NASA DAAC product, Near-Real-Time DMSP SSMIS Daily Polar Gridded Sea Ice Concentrations (NSIDC-0081), as input. The NSIDC DAAC has started the work needed to move to a new source for NSIDC-0081. This involves retrieving F18 and F16 satellite brightness temperatures from our data providers and then implementing parallel processing for ice concentration to determine which satellite will be best suited to continue the time series. The satellite selected will be the primary replacement for F17, but should that satellite fail, we will be able to switch to the other one without a service interruption.

An interim version of the NSIDC-0081 data stream will be used for the ASINA product, which is based on the Sea Ice Index, to continue to report on sea ice conditions. However, the Sea Ice Index processing itself will not resume until a version of NSIDC-0081 is available that is vetted by the science team.

Users may want to explore daily arctic-wide ice extent from the NIC/NSIDC MASIE product as an alternative product for the Northern Hemisphere. The MASIE ice extent record is not consistent with that from the Sea Ice Index, however, nor is it necessarily internally consistent. See the MASIE documentation in order to gain a better understanding of how the product is created.

Having recently discussed the pros and cons of MASIE with Walt Meier of NASA we’ll stick with metrics derived from JAXA’s AMSR2 numbers here at Great White Con. This is how they look at the moment.

NSIDC has obtained data from the DMSP F-18 satellite and is in the process of intercalibrating the F-18 data with F-17 data. Intercalibration addresses differences between the series of sensors, in order to provide a long-term, consistent sea ice record. While this work continues, we are displaying the uncalibrated F-18 data in the daily extent image. The daily time series graph shows F-17 data through March 31, and F-18 data from April 1 forward. Initial evaluation of the uncalibrated F-18 data indicates reasonable agreement with F-17, but the data should be considered provisional and quantitative comparisons with other data should not be done at this time.

Because these are provisional data, the Sea Ice Index has not been updated and continues to display only F-17 data through March 31. We expect to make the F-18 data available in Charctic soon.